Expander Plug

The expander plug is a small board with an I2C expander chip on it with 8 general-purpose digital I/O lines. Each of the lines can be configured individually as input, or as open-collector output, or as regular output. The 2x6-pin connector has the 8 I/O signals, +3.3V and ground, as well as the raw PWR voltage and the IRQ line.

The Breadboard Connector can be used with this plug by attaching it to pins 1..8 of the on-board connector:

An I2C bus running at 3.3V is used for I/O, with all the power and signal lines brought out to to both sides of the board to allow daisy-chaining with other I2C-conformant boards.


There are two solder jumpers to configure each plug for one of the following 7-bit I2C addresses:

Header Pinouts

Design Info

Dimensions: 21.1 x 24.1 mm (Expander Plug) and 21.1 x 11.5 (Breadboard Connector)
CadSoft EAGLE design files: see below.
This plug can be operated at 5V as well as 3.3V.

This board uses the conventions of a JeePlug and can be used with the ports on a JeeNode. It can also be used with other boards and MCU’s, if you hook it up properly and adapt the interface code for it.

How to Get It

Related Weblog Posts

Also available in: PDF HTML TXT